1. Field
Embodiments of the present invention relate to medical methods and apparatus, and more particularly to a method and apparatus for minimally invasive total- or hemi-hip arthroplasty.
2. Description of the Related Art
Early methods and apparatus for performing total hip replacement generally involve a long incision and with open visualization of the trochanteric region of the femur, the femoral head and the acetabulum. However, such techniques result in substantial dissection and disruption of muscles and tissues around the hip joint. The substantial disruption of the tissues creates risk of dislocation and can require months for rehabilitation and healing.
Some less invasive or minimally invasive techniques for total hip replacement have also been described. See, e.g., U.S. Pat. Nos. 7,004,972, 6,991,656 or 6,695,850, the entireties of the contents of which are incorporated herein by reference. As one example, information published by the American Academy of Orthopaedic Surgeons generally describes minimally invasive techniques that use a 3-6 centimeter incision and, as compared to traditional techniques, involve less splitting or detaching of muscles and tendons and less soft tissue dissection. However, many existing minimally invasive techniques still involve substantial disruption of the soft tissue envelope around the hip joint, including the tissue disruption required to create space in which to place and fit a prosthetic femoral neck and head between the femur and the acetabulum. Moreover, many existing techniques have failed to adequately address the problem of numerous trial reductions and dislocations often required to achieve proper fit of the prosthetics which not only causes additional disruption to the tissues, but also consumes valuable time. For example, some hip arthroplasty procedures involve two relatively large incisions in tissue in order to access the anatomy for insertion of the hip replacement components. Many of these techniques involve significant rotation, dislocation and damage to the bone and surrounding tissue, including muscles, ligaments, blood vessels, and nerves. Sometimes, the leg must be bent up to 60 degrees, with twisting and pinning of the leg, which in roughly 6% of procedures, results in a new bone break during the implantation procedure. In some instances, insertion of hip implant components through two incisions involve significant contortion and damage to tissue, resulting in increased recovery and healing time, and component sizes that are limited in length or dimension for access through the one or two incisions. For example, a stem or intramedullary rod length is often limited or shortened in order to fit in a two incision technique. There is a present need for methods and apparatus that provide for efficient hip replacement while maintaining the integrity of the tissues proximate to the hip joint.